Flow timed????

[carcrafter22]

I will have my pump back by friday and need to get some knowledge on setting it up. Eric at sheid diesel told me I will need to "flow time" the pump.

Can anyone explain how to "flow time" a bosch A pump?

Is there another name for it? maybe spill port timing? Any websites I can look on to read about it?

thanks
Randy

 

[loganp]

We were told in class that it's also called the "lift to port closure" timing method. You need to figure out how many seconds between drips out of the injector line you need to get the timing you want.

 

[72chevy]

Cummins repair manual tells you how.

 

[Bponci]

Its called spill port timing. Yes, its very accurate as long as your tdc is correct on the engine.

 

[Timebomb]

Its called spill port timing. Yes, its very accurate as long as your tdc is correct on the engine.

Is it the same as putting the engine on TDC and seting plunger lift were you want it ?

 

[White Knight]

To spill port time a pump you want to set the pump to when fuel begins to be injected then rotate the engine to the position to before TDC that you desire. Be sure to always come up to the desired positions by rotating direction of rotation to avoid error caused by backlash (ie rotate CCW say 45* then rotate CW to desired position).

To find when the injection event is to start flow fuel through the pump and rotate the pump camshaft (can still be connected to engine to do this) until fuel stops flowing through #1 plunger assembly with the delivery valve removed.

A timing wheel or timing tape is needed. But no dial indicator or holder except if you want exact TDC.



Diesel Power Magazine had a P-pump article that surprisingly had some helpful information in it Click Here
Specifically:

Do-It-Yourself P7100 Timing
First, check the injection pump specification plate on the engine for the port closure value. Then, with a breaker bar on the crankshaft bolt, manually turn the crankshaft in the engine's direction of rotation to position the #1 piston on the compression stroke. Locate the engine calibration scale that is usually found on the front pulley, harmonic damper, or the flywheel. Position the crankshaft approximately 20 degrees before the port closure specification. For example, if the specification is 10 degrees, you would set the crankshaft at 30 degrees.

Remove the high-pressure pipe from the delivery valve on the injection pump #1 cylinder. Unscrew the delivery valvebody and remove the delivery valve core and spring. With a scrap piece of injection line from a salvage yard or engine shop, install it as a test spill tube on the injection pump. A discarded high-pressure pipe cut neatly and shaped into a gooseneck is all that is required.
Use the hand primer pump to charge the gallery. The pressure created by the pump will be insufficient to open the delivery valves, which means the fuel will exit through the spill tube you have attached to the #1 port. The fuel should exit in a steady stream, so have a friend hold a coffee can or other container under the tube.

Then, slowly and smoothly turn the engine over with the breaker bar in the direction of rotation while observing the stream of fuel from the test tube. When the injection pump plunger leading edge rises to trap off the spill port, the steady stream of fuel exiting the test tube will first break up into droplets and then cease as the plunger passes the spill port.

The critical thing here is to locate the pump precisely (through the movement of the crankshaft) at port closure. At that time, the flow at the test tube should exist but be minimal; 2 to 6 drops per 10 seconds.

Now check the engine timing marks. Where the crankshaft position produced the drip from the test tube is the port closure. The crankshaft should be within one degree of the listed specification if the injection pump is timed properly.
If the pump timing is found to be wrong, remove the accessory drive cover plate. To do so, loosen and remove the fasteners that connect the pump drive gear to the pump drive plate. With a breaker bar on the crankshaft bolt, turn the crank to the port closure specification. By uncoupling the pump drive plate from the pump drive gear, the pump will remain stationary at port closure on the #1 cylinder while you turn the crankshaft. When the engine is in the correct position, torque the fasteners that couple the pump drive gear to the pump drive plate. Turn the engine backward approximately 20 degrees before the port closure timing specification and then recheck the setting.

Does that make sense? :Cheer:

 

[dzlfarmboy]

For those wanting a better idea of whats being discused take a look at the posted picture of plungers and how the helix's are cut to deliver more or less fuel depending on how much they are turned with the rack travel.

As fuel flows in and the plunger comes up depending on where the helix is determines how much fuel is getting delivered based on when it reaches port closure.

 

[Big Blue24]

So when guys rotate the barrels for more fuel, they are changing orientation/rotating to spill ports. By looking at the diagram, it would seem that rotating the barrel counter clockwise will move the port to where the plunger must lift further before bleeding fuel out of the port and ending the injection event.

Is there a maximum amount that the rack can travel= maximum amount that the helices can be rotated?

 

[Timebomb]

I understand some guys are trying this on there trucks. IMO I would leave this to an ADS diesel shop. Every B&P is going to be different depending on ware on the pump. There is no way to know accuratley how each B&P is effected unless its on a stand. Again this is my thoughts.